Absorption refrigeration



March 23, 1954 w. G. KOGEL 2,672,737 ABSORPTION REFRIGERATION Filed Aug.19, 1950 INVENTOR.

A ATTORNEY Patented Mar. 23, 1954 UNITED STATES PATENT OFFICE Wilhelm:Georg .Kiigel, Stockholm, Sweden, 1

.signor .to Aktiebolaget Elektrolux, Stockholm, \Sweden, acorporation ofSweden Application August =19, 1950, Serial No. 180,47 '7 iclaimspriority, application Sweden .August 25, 1949 "1 Claim. (01.'62--'1=19.5)

My invention relates .to refrigeration systems of the absorption type.

It is an object of my invention .to effect imintothe lower end of the Inthedrawing the heating tube 12 is arranged-to 'be heated by a gas burnerI5 to-whichasuitablercombustible gas isdelivered throughaconduit l6.

Theheat supplied to the boiler. and" its concooled. condenser liquefied.Liquid spectively, inrefrigerant vapor. Since the column of gas rich inrefrigerantvaporand flowing from cooling element 2| to the absorber coil.21 isheavier than the gas weakin refrigerant and fiowingfrom .theabsorber coil 21 to cooling elein the manner described.

Absorption solution enriched in refrigerant flows from the absorbervessel .26 through a con- (111M130 and an outerpassage or pipe. 3 l ofzliquid heat exchanger 32-disposed about thelower part lower end of avapor lift pipe or tubeu33' through 5 which liquid is raised byvapor-liquid lift action in the vapor expulsion-unit l0. Refrigerantvapor expelled out 'of solution in boiler'l rfiows upwardly from thevapor expulsion unit I0 to the condenser I9 in a path of flowto bedescribed more fully hereinafter. The absorption liquid from whichrefrigerant vapor has been-expelled fiowsfrom the'boiler H through aconduit 35, inner pipe orpassage 36 of liquid heat exchangerjz and.conduit 28 ,intothe upper. part of absorber coil 21. The circulation ofabsorption solution in the liquid circuit just described is effected byraising of liquid through pipe 33. The outlet end of condenser i9 isconnected by an upper extension of conduit 23, vessel 3? and conduit 38to a part of the gas circuit, as at one end of gas heat exchanger 24,for example, so that any inert gas which may pass through the condenserl9 can flow into the gas circuit. Refrigerant vapor not liquefied in thecondenser flows through the upper part ofconduit '20- to displace inertgas in vessel 31 and force such gas into the gas circuit. The effect offorcing gas into the gas circuit in this manner is to raise the totalpressure in the entire system whereby an adequate condensing pressure isobtainedto insure condensation of refrigerant vapor in condenser (3. Therefrigeration system just described may be controlled by a thermal bulb39 which is affected by a temperature condition of cooling element 2|.As shown, the thermal bulb 39 is arranged in thermal exchange relationwith the bottom part of cooling element 2| and connected by a conduit 40to a control device M which is connected in the fuel supply conduit 53.The thermal bulb 33 and conduit 3 may form part of an expansible fluidthermostat which is charged with a suitable volatile fluid for operatingthe control device 4] with changes in temperature of cooling element 2|,in a manner well known in the art.

When the temperature of cooling element 2i increases due to an increasein load on the cooling element, thermal bulb 39 becomes effective tooperate control device 4! to increase the supply of fuel to burner l5whereby the latter operates with a normal or maximum flame and heat issupplied at maximum heat input to the vapor expulsion unit [3. Underthese conditions refrigerant vapor is expelled from solution in vaporexpulsion unit If! at an increased rate, thereby increasing the amountof refrigerant vapor which condenses in condenser 13 and flows intocooling element 2|.

Conversely, when the temperature of cooling element 2| decreases, thethermal bulb 33 becomes effective to operate controldevice 4| todecrease the supply of fuel to burner i5 whereby the latter operateswith a pilot flame and heat is supplied at a minimumior reducedheatinput to the vapor expulsion unit it. conditions, the rate at whichrefrigerant vapor is expelled out of solution in the vapor expulsionunit ,I 0 is reduced, thereby decreasing the amount of refrigerant vaporwhich denser l9 andflows into cooling element 2!. v

In accordance with my invention I provide an improved vapor expulsionunit for effectively initiating and maintaining circulation ofabsorption solution in the liquid circuit under different conditionsencountered in practice. expulsion unit includes the lift tube or pumppipe 33 connected to receive absorption solution enriched in refrigerantand flowing thereto from the absorber vessel 23 and liquid heatexchanger 32. heat conductively connected at l2 to the heating tube l2to vaporize liquid in thelift tube and effect lifting of liquid by vaporlift action with the aid of vapor thus formed in the lift tube.

The raised liquid'passing from the upper end of lift tube 33 flowsdownwardly through a conduit 43 whose lower end is connected to theboiler l l at a region below the liquid level therein. 7 lifting vaporis separated from the raised liquid condenses in conla outer passage 31of The lifttube33 is and passes from the upper end of lift tube 33through conduit 11 to the condenser 19. The heating tube l2 heatsenriched absorption solution in the boiler or pipe H to cause expulsionof refrigerant vapor from solution. The principal part of the generatedvapor produced in the vapor expulsion un' 13 is expelled from solutionin the boiler I l, and absorption solution weak in refrigerant flowstherefrom through conduit 35, inner passage 36 of liquid heat exchanger32 and conduit 23 into the upper end of absorber coil 21, as previouslyexplained.

Vapor expelledfrom solution in the boiler H flows from the upper partthereof through a conduit 44 which includes a downwardly extendingportion having the lower end thereof connected to the upper section orturn of the liquid heat exchanger 32 at a region 45 which is removedfrom the connection of the lift tube 33 with the liquid heat exchanger.The vapor passes from the lower end of conduit and then in ahorizontally extending direction in intimate contact with absorptionsolution enrichedin refrigerant which is flowing through the extremeupper portion of the outer passage 3 l. of the" liquid heat exchanger.The generated vapor, from boiler ll then passes upwardly in lift tube 33and is utilized to efiect lifting of liquid by vapor lift action. Hence,the vapor generated in boiler, II also finds its way to the upper endofconduit 43 and passes through conduit ll .to the condenser l9. s u VIn view of the foregoing it will now be understood that all ofthegenerated vapor produced in boiler I! is efiectively utilized toraiseliquid by vapor lift action in the lift tube 33. The generated vaporusually is a mixture of refrigerant vapor and absorption liquid vapor;and, when ammonia and water are employed as the refrigerant andabsorption liquid, for example,

- the generated vapor usually is a mixture of am- Under these I Thevapor monia and water, the water vapor may. be removed from ammonia bycooling the mixture to condense out thewater. 1

The absorption liquid passing through theextreme upper section of theliquid heat exchanger passage 3| is relatively rich inrefri erant and ata lowertemperature than ,the generated, vapor, and, in comingin intimatecontact with the eneriched solution, the water vaporiscooled'sufficiently and condenses and in thiswayisrem led fromtheammonia vapor. Thelatent lrea pf condensation resultingfrom-lcQndensatiqn gf water vapor is given up to the enriched absorptionsolution, whereby m amm nia ,VQPQ IJ pelled .outof solution. su h explledv re r ra t vapor .mixes withlrefrigerant vapor ge nerated in theboiler ,i l, and the mixture passes upwardly through the lift tube 33andfl qnduit l] tothe condenser 13. r ,7 i. When-the refrigeration,systemm' is .ini ly placed in operation following a shut. downpe'riodthe liquid levelin conduit 43. is.substantially, .at the level I whichis the liquid level the .ab: sorber vessel 26; -When generated vapor ispro-1- ducedin boiler H the liquid must be depressed in conduit Mthrough a distance before the vapor passes into the outer liquidheat-exchanger passage 3|. i The liquid'column "in the conduit 43'balances 'the vaporpressure maintained-7 in boiler ll under suchoperating" conditions and, in order that the liquid in'cond'uitfl willn'ot block flow of vapor from lift tube 33"int'o 'c oiidiiit 5 theliquid level in boiler l for a distance substantially greater than thedistance h.

The vapor expulsion unit advantages of which the most important iscertain starting under all operating conditions eninput conditions isinitiated, and flowing generated vapor from the boiler II to the lifttube to promote raising or pumping of liquid by vapor lift action.

tion solution at the first region of the outer pas- 10 tion is initiallyraised by vapor lift action with heating said solution to promoteraising thereof in said riser by vapor lift action WhlCh is augmented bysaid boiler vapor, said last-mentioned heating 15 means includingprovisions for heating said upright pipe and being operable to efiectheating of said absorption solution after passing the first region ofthe outer passage of said liquid heat 20 level from the second regionthereof and ineffecregions of the outer passage of said liquid heatexchanger.

5 WILHELM GEORG K6GEL.

References Cited in the file of this patent UNITED STATES PATENTS

